1. Field of the Invention
The present invention relates to a method of forming a spacer using an ink jet system and a method of fabricating a liquid crystal display device, and more particularly, to a method of forming a spacer using an ink jet system and a method of fabricating a liquid crystal display device that maintain a uniform cell gap between a color filter substrate and an array substrate and prevent the generation of stains in a border or overlap region when a spacer is formed by using an ink jet system.
2. Discussion of the Related Art
As the interest in information displays and the demand for portable information devices increase, research of light flat panel displays (FPD) as a substitute for cathode ray tubes (CRT) is ongoing. Particularly, liquid crystal display (LCD) devices are devices for displaying an image using optical anisotropy of a liquid crystal and are being actively used for in notebook computers and a desktop monitors because of their excellent resolution, color display and image quality.
In general, a liquid crystal display device is a display device that displays a desired image by individually supplying data signals corresponding to image information to liquid crystal cells arranged in a matrix and controlling the light transmittance of the liquid crystal cells.
Hereinafter, a liquid crystal display device will be described in detail with reference to FIG. 1.
FIG. 1 is an exploded perspective view schematically illustrating a construction of a liquid crystal display device.
As shown therein, a liquid crystal display device includes a color filter substrate 5 as a first substrate, an array substrate 10 as a second substrate, and a liquid crystal layer 40 interposed between the color filter substrate 5 and the array substrate 10.
The color filter substrate 5 includes a color filter C having red (R), green (G), and blue (B) sub color filters 7, a black matrix 6 that separates the sub color filters 7 from each other and blocks light transmitting the liquid crystal layer 40, and a common electrode 8 that is transparent and applies a voltage to the liquid crystal layer 40.
The array substrate 10 includes gate lines 16 and data lines 17 that are horizontally and vertically arranged and define pixel regions (P). A thin film transistor T (TFT), which is a switching device, is formed at a crossing of the gate line 16 and the data line 17. A pixel electrode 18 is formed on each of the pixel regions P.
The pixel region P is a sub pixel corresponding to one of the sub color filters 7 of the color filter substrate 5, and a color image is obtained by a combination of three types of the sub color filters 7, that is, red, green and blue sub color filters 7. In other words, three sub pixels of red, green and blue combine to thereby form one pixel, and the thin film transistors T are connected to the red, green and blue sub pixels, respectively.
A uniform cell gap between the color filter substrate 5 and the array substrate 10 that have the above-described constructions is maintained by a spacer (not shown). The color filter substrate 5 and the array substrate 10 are attached to each other by a seal pattern (not shown) formed along an outer edge of the color filter substrate 5 and the array substrate 10.
One method for forming the spacer includes randomly dispersing ball spacers, such as glass beads or a plastic beads, on the substrate surface according to a relatively simple process. However, because the ball spacers are randomly dispersed and it may be impossible to fix a position thereof, failure of the alignment layer may result because of movement of the ball spacer. In addition, a light leakage phenomenon occurs around the ball spacer by absorption between liquid crystal molecules adjacent to the ball spacer. Further, as liquid crystal display devices increase in size, it is difficult to maintain an accurate cell gap because of an accumulation phenomenon of the ball spacer. Therefore, an inferior image is generated.
Recently, instead of using ball spacers, a patterned spacer or a column spacer has been used, in which a photolithography process is used for the color filter substrate or an array substrate so as to form a spacer pattern at predetermined positions.
It is possible to prevent generation of light leakage by using a column spacer because it is possible to easily maintain a cell gap and form the column spacer so as to be fixed to a region covered by the black matrix.
However, because the column spacer is formed by performing a photolithography process that includes coating, exposing, developing and etching processes, it takes a large amount of time and money. In addition, since the column spacer is formed by physical and chemical processes like the above, it is likely to generate a defect on neighboring devices.